1. Field of the Invention
This invention relates to an information recording and/or reproducing apparatus capable of recording information on an optical recording medium with a light beam, or reproducing information from an optical recording medium with a light beam. The invention also relates to an optical recording medium capable of recording and/or reproducing information with a light beam.
2. Related Background Art
Hitherto, as an information recording medium for recording and/or reproducing information, there have been known magnetic recording media capable of recording and/or reproducing information magnetically (for example, floppy disks and magnetic cards), and optical recording media capable of recording and reproducing information with a light beam.
There also has been known a disk-like or tape-like medium for use as an optical recording medium.
It is considered that optical cards will be used in many ways, because of easy productivity, good portability, and a good accessibility.
FIG. 1 is a plan view of a typical, conventional optical recording medium as, for example, disclosed in Japanese Laid-Open Patent Application JP-A-02-203467.
Referring to FIG. 1, 1 is an optical card having a rectangular plane shape, with a plurality of tracking tracks 2 running parallel to each other. Between each pair of tracking tracks 2 there are provided data tracks 3 in which information is recorded with a light beam, there being a plurality of data tracks 3 running parallel to each other.
The tracking tracks 2 are used for registration of the position of the recording light beam and/or reproducing light beam when recording data in the data tracks 3 or reproducing data recorded in the data tracks 3.
At both ends of the data tracks 3 there is a track identifier part 4 (hereinafter called a "track ID part 4"). The track ID part 4 contains information that shows a position of each data track 3 and/or address information relating to the data track. This information is previously recorded in the track ID part 4, i.e., is preformatted. Each data track 3 is divided into one or more minimum recording sectors.
Information is recorded in the optical card described above by scanning a light beam modulated in accordance with the information on the data track 3 and focused to a small spot on the card, and making an optically detectable mark in the recording layer.
Any information recorded on the optical card is reproduced by scanning on the data track a light beam having a fixed power which is not capable of recording, and detecting a difference of a quantity of reflected light or transmitted light between the mark and another part of the card.
An information recording and/or reproducing apparatus which records information on an optical card or reproduces information recorded on the optical card may have automatic focusing control means that controls the size of a light spot on the optical card automatically, and automatic tracking control means that controls the position of the light spot automatically.
An outline of a convention optical card and a conventional information recording apparatus has been given above. Recently, however, there has been suggested a hybrid card, which has not only an optical recording layer but also other information storage means, for example, an IC module, a magnetic stripe or embossed visible information.
Furthermore, there have been various kinds of optical cards that have different recording capacity, that is, having a different number of data tracks. FIGS. 2(a)-2(c) are examples of typical views of such optical cards. FIG. 2(a) shows an optical card which has an optical recording area 10 covering almost the whole surface. FIG. 2(b) shows an optical card having visible information (embossed "optical card") with the optical card's recording area 10 being decreased compared to the FIG. 2(a) card. FIG. 2(c) shows an optical card having an IC module so as to have both functions of an optical card and an IC card, with the optical card's recording area 10 being decreased so as to accommodate the IC module.
However, in practice with such various optical recording media having different recording capacity, there is a problem as follows. Access of the recording light beam and/or reproducing light beam to the data track 3 is usually achieved using the information recorded in the track ID part which shows a physical position of the data track. Thus, when the recording and/or reproducing apparatus accepts a track number to be accessed in some form from overall controlling means (for example, a host computer), the recording and/or reproducing apparatus searches the data track to be accessed in accordance with the information of the track ID part to access a desired data track.
Thus, hitherto, when the recording and/or reproducing apparatus accepts a track number, which the optical card to be read does not have, from the overall control means, the apparatus tries to access the track. As a result, the automatic focusing control and/or automatic tracking control is out of control, and then a recording and/or a reproducing error may happen and a lot of time may elapse before the controls resume.
In JP-A-2-203467 described above, the applicant of the present invention discloses an information recording and/or reproducing apparatus for plural types of optical recording media having a discriminating means for discriminating between plural types of optical media, and control means for controlling an area to be recorded or reproduced in accordance with the result of the discrimination by the discriminating means. However, there is no disclosure about a control method for accommodating plural types of optical recording means which have different numbers of tracks.
JP-A-62-239345 discloses an information recording medium provided with an optically detectable mark which shows a kind of an optical recording medium at a data track. However, there is no disclosure of an optical recording medium which complies with the purpose of the present invention.